史元春 照片

史元春

教授

所属大学: 清华大学

所属学院: 计算机科学与技术系

邮箱:
shiyc@tsinghua.edu.cn

个人主页:
https://www.cs.tsinghua.edu.cn/info/1116/3534.htm

个人简介

教育背景 工学学士 (计算机科学与技术), 清华大学, 中国, 1989 工学硕士 (计算机科学与技术), 清华大学, 中国, 1993 工学博士 (计算机科学与技术), 清华大学, 中国, 1999 工作履历 史元春,清华大学计算机科学与技术系教授。她在清华大学获得了博士学位、硕士和学士学位,并于1993年加入清华大学。她在人机交互、普适计算、多媒体等领域的研究成果多次获得学术奖项,包括两项国家科技进步奖,以及CHI、MobileHCI等国际会议的多项最佳论文奖、最佳论文提名奖。近年来,史元春教授在人机交互领域的贡献包括用户行为建模、手机智能交互技术、大屏幕显示与交互装置、VR/AR头盔交互等。她发表了100多篇人机交互领域CS排名为顶级会议和学术期刊的论文,近5年的论文包括30余篇CHI、UIST、Ubicomp、TOCHI和IJHCS论文 工作经历 1993.8-至今: 清华大学计算机科学与技术系教授。1997年晋升副教授,2002年晋升教授 2015.10-至今: 清华大学全球创新学院(GIX),院长 2003.12-2018.4: 清华大学计算机科学与技术系人机交互与媒体集成研究所,所长 2006.12-至今: 普适计算教育部重点实验室主任 2001.8-2002.2: MIT AI实验室,访问学者 教学课程 计算机科学导论 (本科生) , Fall, 2003- 人机交互理论与技术 (本科生) , Fall, 2004- 人机交互接口技术 (研究生) Fall, 2009- 人机交互技术 (研究生,英文授课), Spring, 2011- 分布式多媒体系统与技术 (研究生), Fall, 1995-2010 媒体计算 (本科生) , Fall, 1993-2005 数字逻辑电路 (本科生), Spring, 1993-1995 社会兼职 Chair elect, Technical Committee of HCI, China Computer Foundation (CCF), 2020-2024 Executive Board Member, China Computer Foundation, 2008- Vice Chair, Technical Committee of Intelligent Interaction, China Association of AI, 2016-2020 Co-chair, Workshop of Developing HCI Education Crossing Asia, 2015, Seoul, Korea Vice Chair, Technical Committee of HCI, China Computer Foundation, 2013-2019 Co-chair, ACM Ubicomp, 2011, Beijing, China Chair, ACM SIGCHI Paper Development Lectures on CSCW, CHI and Ubicomp, Beijing, 2010 Vice Chief Editor, Communication of CCF, 2012-2017 Area Editor, PMC(Pervasive and Mobile Computing) , Elsevier, 2010-2014 Editorial Board, Interacting with Computer, 2011- Proceedings co-chair, ACM Multimedia 2009 Vice Chair, CIC/WFEO(World Federation of Engineering Organizations, Standing Committee on Information and Communications), 2008-2010 Chair, Technical Committee of Pervasive Computing, China Computer Foundation, 2005-2012 Proceedings Chair, Pacific-ring Conference on Multimedia, PCM 2001 Proceedings Chair, International Conference of Multimodality Interaction, ICMI 2000 Many: PC member of conferences; Invited and Keynote talks for conferences 奖励与荣誉 2018.12,中国计算机学会优秀博士生论文导师 2017.9 北京市优秀教师 2016.3,北京市三八红旗奖章 2015,国家科技进步二等奖(第一获奖人),普适计算软硬件关键技术与应用 2005,教育部新世纪人才 2001,科技部九五攻关先进个人 1995, 1996, 1998, 1999, 2000, 2001, 2002,多次获得清华大学年度优秀教师奖

研究领域

人机交互 普适计算

近期论文

Mobile and Wearable Interaction Yuntao Wang, Jianyu Zhou, Hanchuan Li, Tengxiang Zhang, Minxuan Gao, Zhuolin Cheng, Chun Yu, Shwetak Patel, Yuanchun Shi: FlexTouch: Enabling Large-Scale Interaction Sensing Beyond Touchscreens Using Flexible and Conductive Materials. IMWUT 3(3): 109:1-109:20 (2019) Zhican Yang, Chun Yu, Xin Yi, Yuanchun Shi: Investigating Gesture Typing for Indirect Touch. IMWUT 3(3): 117:1-117:22 (2019) Zhican Yang, Chun Yu, Fengshi Zheng, Yuanchun Shi: ProxiTalk: Activate Speech Input by Bringing Smartphone to the Mouth. IMWUT 3(3): 118:1-118:25 (2019) Ke Sun, Chun Yu, Yuanchun Shi: Exploring Low-Occlusion Qwerty Soft Keyboard Using Spatial Landmarks. ACM Trans. Comput.-Hum. Interact. 26(4): 20:1-20:33 (2019) [J] Ruolin Wang, Chun Yu, Xing-Dong Yang, Weijie He, Yuanchun Shi: EarTouch: Facilitating Smartphone Use for Visually Impaired People in Mobile and Public Scenarios. CHI 2019: 24:1-13Honorable Mention Award Guanhong Liu, Xianghua Ding, Chun Yu, Lan Gao, Xingyu Chi, Yuanchun Shi: "I Bought This for Me to Look More Ordinary": A Study of Blind People Doing Online Shopping. CHI 2019: 372:1-11 Weinan Shi, Chun Yu, Shuyi Fan, Feng Wang, Tong Wang, Xin Yi, Xiaojun Bi, Yuanchun Shi: VIPBoard: Improving Screen-Reader Keyboard for Visually Impaired People with Character-Level Auto Correction. CHI 2019: 517:1-12Honorable Mention Award Yiqin Lu, Chun Yu, Shuyi Fan, Xiaojun Bi, Yuanchun Shi: Typing on Split Keyboards with Peripheral Vision. CHI 2019: 200:1-12 Chun Yu, Xiaoying Wei, Shubh Vachher, Yue Qin, Chen Liang, Yueting Weng, Yizheng Gu, Yuanchun Shi: HandSee: Enabling Full Hand Interaction on Smartphone with Front Camera-based Stereo Vision. CHI 2019: 705:1-13 Yizheng Gu, Chun Yu, Zhipeng Li, Weiqi Li, Shuchang Xu, Xiaoying Wei, Yuanchun Shi: Accurate and Low-Latency Sensing of Touch Contact on Any Surface with Finger-Worn IMU Sensor. UIST 2019: 1059-1070 Mingyuan Zhong, Chun Yu, Qian Wang, Xuhai Xu, Yuanchun Shi: ForceBoard: Subtle Text Entry Leveraging Pressure. CHI 2018: 528:1-10 Ke Sun, Chun Yu, Weinan Shi, Lan Liu, Yuanchun Shi: Lip-Interact: Improving Mobile Device Interaction with Silent Speech Commands. UIST 2018: 581-593 Yuanchun Shi: Interpreting User Input Intention in Natural Human Computer Interaction. UMAP 2018: 277-278, keynote abstract Xin Yi, Chun Yu, Weinan Shi, Yuanchun Shi: Is it too small?: Investigating the performances and preferences of users when typing on tiny QWERTY keyboards. Int. J. Hum.-Comput. Stud. 106: 44-62 (2017) [J] Ke Sun, Yuntao Wang, Chun Yu, Yukang Yan, Hongyi Wen, Yuanchun Shi: Float: One-Handed and Touch-Free Target Selection on Smartwatches. CHI 2017: 692-704 Xin Yi, Chun Yu, Weijie Xu, Xiaojun Bi, Yuanchun Shi: COMPASS: Rotational Keyboard on Non-Touch Smartwatches. CHI 2017: 705-715Honorable Mention Award Xin Yi, Chun Yu, Weinan Shi, Xiaojun Bi, Yuanchun Shi: Word Clarity as a Metric in Sampling Keyboard Test Sets. CHI 2017: 4216-4228 Chun Yu, Ke Sun, Mingyuan Zhong, Xincheng Li, Peijun Zhao, Yuanchun Shi: One-Dimensional Handwriting: Inputting Letters and Words on Smart Glasses. CHI 2016: 71-82 Chun Yu, Hongyi Wen, Wei Xiong, Xiaojun Bi, Yuanchun Shi: Investigating Effects of Post-Selection Feedback for Acquiring Ultra-Small Targets on Touchscreen. CHI 2016: 4699-4710 Yuntao Wang, Ke Sun, Lu Sun, Chun Yu, Yuanchun Shi: SkinMotion: what does skin movement tell us? UbiComp Adjunct 2016: 914-917 Yuntao Wang, Chun Yu, Lin Du, Jin Huang, Yuanchun Shi: BodyRC: Exploring Interaction Modalities Using Human Body as Lossy Signal Transmission Medium. UIC/ATC/ScalCom 2014: 260-267Best Paper Award Yuntao Wang, Chun Yu, Jie Liu, Yuanchun Shi: Understanding performance of eyes-free, absolute position control on touchable mobile phones. Mobile HCI 2013: 79-88Honorable Mention Award Mingming Fan, Donald J. Patterson, Yuanchun Shi: When camera meets accelerometer: a novel way for 3d interaction of mobile phone. Mobile HCI (Companion) 2012: 131-136 Wenchang Xu, Jie Liu, Chun Yu, Yuanchun Shi: Digging unintentional displacement for one-handed thumb use on touchscreen-based mobile devices. Mobile HCI 2012: 261-270 Yue Shi, Yuanchun Shi, Xia Wang: Fall Detection on Mobile Phones Using Features from a Five-Phase Model. UIC/ATC 2012: 951-956 Yue Shi, Yuanchun Shi, Jie Liu: A rotation based method for detecting on-body positions of mobile devices. UbiComp 2011: 559-560 Liang Zhang, Yuanchun Shi, Mingming Fan: UCam: direct manipulation using handheld camera for 3d gesture interaction. ACM Multimedia 2008: 801-804 VR/AR Input Yukang Yan, Chun Yu, Xin Yi, Yuanchun Shi: HeadGesture: Hands-Free Input Approach Leveraging Head Movements for HMD Devices. IMWUT 2(4): 198:1-198:23 (2018) Yukang Yan, Chun Yu, Xiaojuan Ma, Shuai Huang, Hasan Iqbal, Yuanchun Shi: Eyes-Free Target Acquisition in Interaction Space around the Body for Virtual Reality. CHI 2018: 42:1-13 Yukang Yan, Chun Yu, Xiaojuan Ma, Xin Yi, Ke Sun, Yuanchun Shi: VirtualGrasp: Leveraging Experience of Interacting with Physical Objects to Facilitate Digital Object Retrieval. CHI 2018: 78:1-13 Yiqin Lu, Chun Yu, Xin Yi, Yuanchun Shi, Shengdong Zhao: BlindType: Eyes-Free Text Entry on Handheld Touchpad by Leveraging Thumb's Muscle Memory. IMWUT 1(2): 18:1-18:24 (2017) Chun Yu, Yizheng Gu, Zhican Yang, Xin Yi, Hengliang Luo, Yuanchun Shi: Tap, Dwell or Gesture?: Exploring Head-Based Text Entry Techniques for HMDs. CHI 2017: 4479-4488 Xin Yi, Chun Yu, Mingrui Zhang, Sida Gao, Ke Sun, Yuanchun Shi: ATK: Enabling Ten-Finger Freehand Typing in Air Based on 3D Hand Tracking Data. UIST 2015: 539-548 ition Xiao Zhang, Yongqiang Lyu, Tong Qu, Pengfei Qiu, Xiaomin Luo, Jingyu Zhang, Shunjie Fan, Yuanchun Shi: Photoplethysmogram-based Cognitive Load Assessment Using Multi-Feature Fusion Model. TAP 16(4): 19:1-19:17 (2019) [J] Xiao Zhang, Yongqiang Lyu, Xin Hu, Ziyue Hu, Yuanchun Shi, Hao Yin: Evaluating Photoplethysmogram as a Real-Time Cognitive Load Assessment during Game Playing. Int. J. Hum. Comput. Interaction 34(8): 695-706 (2018) [J] Xiao Zhang, Yongqiang Lyu, Xiaomin Luo, Jingyu Zhang, Chun Yu, Hao Yin, Yuanchun Shi: Touch Sense: Touch Screen Based Mental Stress Sense. IMWUT 2(2): 87:1-87:18 (2018) Yong-Jin Liu, Minjing Yu, Guozhen Zhao, Jinjing Song, Yan Ge, Yuanchun Shi: Real-Time Movie-Induced Discrete Emotion Recognition from EEG Signals. IEEE Trans. Affective Computing 9(4): 550-562 (2018) [J] Yongqiang Lyu, Xiao Zhang, Xiaomin Luo, Ziyue Hu, Jingyu Zhang, Yuanchun Shi: Non-Invasive Measurement of Cognitive Load and Stress Based on the Reflected Stress-Induced Vascular Response Index. TAP 15(3): 17:1-17:17 (2018) [J] Guozhen Zhao, Yong-Jin Liu, Yuanchun Shi: Real-Time Assessment of the Cross-Task Mental Workload Using Physiological Measures During Anomaly Detection. IEEE Trans. Human-Machine Systems 48(2): 149-160 (2018) [J] Yongqiang Lyu, Xiaomin Luo, Jun Zhou, Chun Yu, Congcong Miao, Tong Wang, Yuanchun Shi, Ken-ichi Kameyama: Measuring Photoplethysmogram-Based Stress-Induced Vascular Response Index to Assess Cognitive Load and Stress. CHI 2015: 857-866Honorable Mention Award Jin Huang, Chun Yu, Yuntao Wang, Yuhang Zhao, Siqi Liu, Chou Mo, Jie Liu, Lie Zhang, Yuanchun Shi: FOCUS: enhancing children's engagement in reading by using contextual BCI training sessions. CHI 2014: 1905-1908 GUI Efficiency Wenchang Xu, Chun Yu, Jie Liu, Yuanchun Shi: RegionalSliding: Facilitating small target selection with marking menu for one-handed thumb use on touchscreen-based mobile devices. Pervasive and Mobile Computing 17: 63-78 (2015) [J] Wenchang Xu, Chun Yu, Songmin Zhao, Jie Liu, Yuanchun Shi: Facilitating parallel web browsing through multiple-page view. CHI 2013: 2167-2170Honorable Mention Award Chun Yu, Ravin Balakrishnan, Ken Hinckley, Tomer Moscovich, Yuanchun Shi: Implicit bookmarking: Improving support for revisitation in within-document reading tasks. Int. J. Hum.-Comput. Stud. 71(3): 303-320 (2013) [J] Jie Liu, Wenchang Xu, Yuanchun Shi: AutoWeb: automatic classification of mobile web pages for revisitation. Mobile HCI 2012: 191-200 Chun Yu, Yue Shi, Xinliang Wang, Yuanchun Shi: Watching you moving the mouse, i know who you are. CHI Extended Abstracts 2012: 2661-2666 Jie Liu, Chun Yu, Wenchang Xu, Yuanchun Shi: Clustering web pages to facilitate revisitation on mobile devices. IUI 2012: 249-252 Chun Yu, Yuanchun Shi, Ravin Balakrishnan, Xiangliang Meng, Yue Suo, Mingming Fan, Yongqiang Qin: The satellite cursor: achieving MAGIC pointing without gaze tracking using multiple cursors. UIST 2010: 163-172 Wenchang Xu, Xin Yang, Yuanchun Shi: Enhancing browsing experience of table and image elements in web pages. ICMI 2010: 24:1-24:8 Xin Yang, Peifeng Xiang, Yuanchun Shi: Finding User's Interest Blocks using Significant Implicit Evidence for Web Browsing on Small Screen Devices. World Wide Web 12(2): 213-234 (2009) Tabletop and Large Screen Interaction Weinan Shi, Chun Yu, Xin Yi, Zhen Li, Yuanchun Shi: TOAST: Ten-Finger Eyes-Free Typing on Touchable Surfaces. IMWUT 2(1): 33:1-33:23 (2018) Zhun Qu, Chun Yu, Yue Shi, Jin Huang, Li Tian, Yuanchun Shi: TangramTheatre: presenting children's creation on multimodal tabletops. CHI Extended Abstracts 2014: 2077-2082 Yuntao Wang, Chun Yu, Yuhang Zhao, Jin Huang, Yuanchun Shi: Defining and Analyzing a Gesture Set for Interactive TV Remote on Touchscreen Phones. UIC/ATC/ScalCom 2014: 362-365 Yuhang Zhao, Alexis Hope, Jin Huang, Yoel Sumitro, James A. Landay, Yuanchun Shi: Hero: designing learning tools to increase parental involvement in elementary education in china. CHI Extended Abstracts 2013: 637-642 Yuntao Wang, Chun Yu, Yongqiang Qin, Dan Li, Yuanchun Shi: Exploring the effect of display size on pointing performance. ITS 2013: 389-392 Yongqiang Qin, Chenjun Wu, Yuanchun Shi: PiMarking: co-located collaborative digital annotating on large tabletops. ITS 2012: 395-398 Yongqiang Qin, Jie Liu, Chenjun Wu, Yuanchun Shi: uEmergency: a collaborative system for emergency management on very large tabletop. ITS 2012: 399-402 Haijun Xia, Jingning Zhang, Yeshuang Zhu, Chun Yu, Yuanchun Shi: Mobile assistant: enhancing desktop interaction using mobile phone. ITS 2012: 379-382 Chenjun Wu, Yue Suo, Chun Yu, Yuanchun Shi, Yongqiang Qin: uPlatform: A Customizable Multi-user Windowing System for Interactive Tabletop. HCI (1) 2011: 507-516 Pierre Dragicevic, Yuanchun Shi: Visualizing and manipulating automatic document orientation methods using vector fields. ITS 2009: 65-68 Xiaojun Bi, Yuanchun Shi, Xiaojie Chen: uPen: A Smart Pen-liked Device for Facilitating Interaction on Large Displays. Tabletop 2006: 160-168 Liang Zhang, Yuanchun Shi, Jichun Chen: Drag and Drop by Laser Pointer: Seamless Interaction with Multiple Large Displays. UIC 2006: 12-20 Hao Jiang, Eyal Ofek, Neema Moraveji, Yuanchun Shi: Direct pointer: direct manipulation for large-display interaction using handheld cameras. CHI 2006: 1107-1110 Smart Space and Ubicomp Tengxiang Zhang, Xin Yi, Ruolin Wang, Yuntao Wang, Chun Yu, Yiqin Lu, Yuanchun Shi: Tap-to-Pair: Associating Wireless Devices with Synchronous Tapping. IMWUT 2(4): 201:1-201:21 (2018) Tengxiang Zhang, Xin Yi, Chun Yu, Yuntao Wang, Nicholas Becker, Yuanchun Shi: TouchPower: Interaction-based Power Transfer for Power-as-needed Devices. IMWUT 1(3): 121:1-121:20 (2017)Discussion Paper Award Tengxiang Zhang, Nicholas Becker, Yuntao Wang, Yuan Zhou, Yuanchun Shi: BitID: Easily Add Battery-Free Wireless Sensors to Everyday Objects. SMARTCOMP 2017: 1-8Honorable Mention Award Jie Liu, Yongqiang Qin, Qiang Yang, Chun Yu, Yuanchun Shi: A Tabletop-Centric Smart Space for Emergency Response. IEEE Pervasive Computing 14(2): 32-40 (2015) [J] Gang Pan, Li Zhang, Zhaohui Wu, Shijian Li, Laurence T. Yang, Man Lin, Yuanchun Shi: Pervasive Service Bus: Smart SOA Infrastructure for Ambient Intelligence. IEEE Intelligent Systems 29(4): 52-60 (2014) [J] Baopeng Zhang, Yuanchun Shi, Xin Xiao: A Policy-Driven Service Composition Method for Adaptation in Pervasive Computing Environment. Comput. J. 53(2): 152-165 (2010) [J] Yue Suo, Chenjun Wu, Yongqiang Qin, Chun Yu, Yu Zhong, Yuanchun Shi: HouseGenie: Universal Monitor and Controller of Networked Devices on Touchscreen Phone in Smart Home. UIC/ATC Workshops 2010: 487-489Best Demo Award Yue Suo, Jingyu Li, Yuanchun Shi, Peifeng Xiang: Baton: a service manager for better sustaining agent coordination in smart spaces. Int. J. Pervasive Computing and Communications 5(2): 104-126 (2009) [J] Yue Suo, Naoki Miyata, Hiroki Morikawa, Toru Ishida, Yuanchun Shi: Open Smart Classroom: Extensible and Scalable Learning System in Smart Space Using Web Service Technology. IEEE Trans. Knowl. Data Eng. 21(6): 814-828 (2009) IEEE China Student Paper Contest Gold Prize [J] Xiang Li, Ling Feng, Lizhu Zhou, Yuanchun Shi: Learning in an Ambient Intelligent World: Enabling Technologies and Practices. IEEE Trans. Knowl. Data Eng. 21(6): 910-924 (2009) [J] Weijun Qin, Daqing Zhang, Yuanchun Shi, Kejun Du: Combining User Profiles and Situation Contexts for Spontaneous Service Provision in Smart Assistive Environments. UIC 2008: 187-200 Baopeng Zhang, Yuanchun Shi, Xin Xiao: A Peer-to-Peer Semantic-Based Service Discovery Method for Pervasive Computing Environment. UIC 2007: 195-204 Yuanchun Shi, Weikai Xie, Guangyou Xu, Runting Shi, Enyi Chen, Yanhua Mao, Fang Liu: The Smart Classroom: Merging Technologies for Seamless Tele-education. IEEE Pervasive Computing 2(2): 47-55 (2003) [J] Weikai Xie, Yuanchun Shi, Guangyou Xu, Yanhua Mao: Smart Platform - A Software Infrastructure for Smart Space (SISS). ICMI 2002: 429-436 Multimedia Yeshuang Zhu, Yuntao Wang, Chun Yu, Shaoyun Shi, Yankai Zhang, Shuang He, Peijun Zhao, Xiaojuan Ma, Yuanchun Shi: ViVo: Video-Augmented Dictionary for Vocabulary Learning. CHI 2017: 5568-5579 Yeshuang Zhu, Shichao Yue, Chun Yu, Yuanchun Shi: CEPT: Collaborative Editing Tool for Non-Native Authors. CSCW 2017: 273-285 Xin Xiao, Qian Zhang, Yuanchun Shi, Yuan Gao: How Much to Share: A Repeated Game Model for Peer-to-Peer Streaming under Service Differentiation Incentives. IEEE Trans. Parallel Distrib. Syst. 23(2): 288-295 (2012) [J] Xin Xiao, Yuanchun Shi, Qian Zhang, Jianhua Shen, Yuan Gao: Toward Systematical Data Scheduling for Layered Streaming in Peer-to-Peer Networks: Can We Go Farther?. IEEE Trans. Parallel Distrib. Syst. 21(5): 685-697 (2010) [J] Xin Xiao, Yuanchun Shi, Yuan Gao, Qian Zhang: LayerP2P: A New Data Scheduling Approach for Layered Streaming in Heterogeneous Networks. INFOCOM 2009: 603-611 Xin Xiao, Yuanchun Shi, Yuan Gao: On optimal scheduling for layered video streaming in heterogeneous peer-to-peer networks. ACM Multimedia 2008: 785-788 Peifeng Xiang, Xin Yang, Yuanchun Shi: Web Page Segmentation Based on Gestalt Theory. ICME 2007: 2253-2256 Xin Xiao, Yuanchun Shi, Meng Zhang: An Investigation and a Preventing Strategy for the Redundant Packets in P2P Networks with Push Method. ICME 2007: 2162-2165 Nan Zhang, Yuanchun Shi, Bin Chang: Degree Pre-Reserved Hierarchical Tree for Multimedia Multicast. ICME 2006: 1209-1212 Peifeng Xiang, Yuanchun Shi: Recovering semantic relations from web pages based on visual cues. IUI 2006: 342-344 Peifeng Xiang, Xin Yang, Yuanchun Shi: Effective Page Segmentation Combining Pattern Analysis and Visual Separators for Browsing on Small Screens. Web Intelligence 2006: 831-840 Xin Xiao, Yuanchun Shi, Nan Zhang: Ermdclime: Enabling Real-time Multimedia Discussion for Collaborative Learning in Mobile Environment. ICME 2006: 2093-2096 Xin Xiao, Yuanchun Shi, Weisheng He: A Novel Approach for Sharing White Board Between PC and PDAs with Multi-users. EUC 2006: 1129-1138 Weisheng He, Yuanchun Shi, Xin Xiao: Auto-summarization of Multimedia Meeting Records Based on Accessing Log. PCM (1) 2005: 809-819 Yi Che, Runting Shi, Yuanchun Shi: TORM: a hybrid multicast infrastructure for interactive distance learning. ICME 2004: 1595-1598 Kun Tan, Yuanchun Shi, Guangyou Xu: A Pragmatic Semantic Reliable Multicast Architecture for Distant Learning. ICMI 2000: 658-665